The role of foliar litter-fall in forming channel morphology step-pool of high-gradient streams in Moravskoslezské Beskydy Mts.

Abstract

Channel morphology step-pool represents a morphodynamic complex influenced by large woody debris and litter-fall. The aim of this paper is to determine the impact of litter-fall on the channel morphology step-pool. General conclusions regarding the influence of litter-fall on channel morphology step-pool were based on results of geomorphological analyses. The study showed differences between river segments with or without foliaged steps. The pools following foliaged steps have a finer grain size composition of sediment. They are also larger, shallower and have a higher retention capacity. Foliaged steps help to decrease potential energy of water more effectively. If the litter-fall is permanently preserved at the step, it makes it more resistant to extreme water flows. As a result, it enables the development of a fully functional channel morphology step-pool.